[ovs-dev] [PATCH 1/3] ofp-actions: helper functions for of12 set-field action

Simon Horman horms at verge.net.au
Fri Sep 14 03:05:44 UTC 2012


On Thu, Sep 13, 2012 at 01:06:09PM -0700, Ben Pfaff wrote:
> I get rejects on this against commit 307975da7 currently on master.
> 
> As long as it needs a rebase anyhow, I see a few more changes I'd
> like:
> 
>         * The struct ofp12_action_set_field change looks good but the
>           line "- Exactly oxm_len bytes containing a single OXM TLV,
>           then" in the comment above it can now be deleted.
> 
>         * In set_field_format(), "load->dst.ofs" should now be changed
>           to just 0 since we now right-justify the data within the
>           mf_subvalue.
> 
>         * I think that this:
> > * Accept non-OXM fields in nxm_reg_load_from_openflow12_set_field()
>           didn't quite get done, since I still see the mf->oxm_header
>           == 0 check in nxm_reg_load_from_openflow12_set_field().
> 
>         * What's the "nast" in set_field_to_nast() stand for?  nxast
>           stands for "Nicira eXtension Action <something> Type", but
>           set-field isn't a Nicira extension.
> 
>         * The loop in nxm_reg_load_to_nxast() is very similar to a
>           loop in learn_execute().  Can we factor it out into a helper
>           function?

Hi Ben,

I think that the patch below addresses all of the points above.

From: Isaku Yamahata <yamahata at valinux.co.jp>

ofp-actions: helper functions for of12 set-field action

Signed-off-by: Isaku Yamahata <yamahata at valinux.co.jp>
Signed-off-by: Simon Horman <horms at verge.net.au>

---

v7 (draft) [Simon Horman]
* Updated OXM comment in ofp12_action_set_field
* Use offset of 0 in set_field_format() as values are right-justified
* Remove OXM-only restriction in nxm_reg_load_from_openflow12_set_field()
* Rename set_field_to_nast() -> set_field_to_ofst()
  - nast: Nicira eXtension Action <something> Type
  - ofast: Open Flow Action <something> Type
* Provide helper function, nxm_reg_split(), to share code between
  nxm_reg_load_to_nxast() and learn_execute().

v6 [Simon Horman]
* Change ofp12_action_set_field so that the last element is
  ovs_be32 dst rather than uint8_t field[4].
  This avoids some casting when the field is used.
* Use is_all_zeros()
* Accept non-OXM fields in nxm_reg_load_from_openflow12_set_field()
* Leave nxm_reg_load_check() unmodified, the NXM checks should be sufficient
* Save subvalue right-justified in nxm_reg_load_from_openflow12_set_field()
* Add room for value and padding in nxm_reg_load_to_nxast()
* If outputing a flow using OpenFlow 1.1 or 1.2 then split any
  set-field actions into NXM load actions

v5 [Simon Horman]
* Do not add mf_check_dst_oxm(), just use mf_check_dst().

v4 [Simon Horman]
* Remove utilities/ovs-ofctl.c hunk, introduced in v3,
  which belongs in a different patch
* Make use of new oxm_writable field in struct mf_subfield
  to implement mf_check_dst_oxm(). This provides more
  strict checking than the previous implementation.
* Do not call pre-requisites explicitly in mf_are_prereqs_ok()
  - It will segfault as flow is NULL
  - It would be called by mf_is_value_valid() if
    flow was not NULL
* Correct byte-order issues in nxm_reg_load_from_openflow12_set_field()
* Add set_field_format() and use it in nxm_format_reg_load()
* Update to use mf_subfield

v3 [Simon Horman]
* Add (now) missing cases to nxm_reg_load_check()

v2 [Isaku Yamahata]
* First post

fix1

fix2
---
 include/openflow/openflow-1.2.h |    3 +-
 lib/learn.c                     |   31 +++++----
 lib/nx-match.c                  |  145 +++++++++++++++++++++++++++++++++++++--
 lib/nx-match.h                  |    6 ++
 4 files changed, 163 insertions(+), 22 deletions(-)

diff --git a/include/openflow/openflow-1.2.h b/include/openflow/openflow-1.2.h
index 64bc993..f6befdb 100644
--- a/include/openflow/openflow-1.2.h
+++ b/include/openflow/openflow-1.2.h
@@ -221,12 +221,11 @@ enum ofp12_controller_max_len {
 struct ofp12_action_set_field {
     ovs_be16 type;                  /* OFPAT12_SET_FIELD. */
     ovs_be16 len;                   /* Length is padded to 64 bits. */
+    ovs_be32 dst;                   /* OXM TLV header */
     /* Followed by:
-     * - Exactly oxm_len bytes containing a single OXM TLV, then
      * - Exactly ((oxm_len + 4) + 7)/8*8 - (oxm_len + 4) (between 0 and 7)
      *   bytes of all-zero bytes
      */
-    uint8_t field[4];               /* OXM TLV - Make compiler happy */
 };
 OFP_ASSERT(sizeof(struct ofp12_action_set_field) == 8);
 
diff --git a/lib/learn.c b/lib/learn.c
index b9bbc97..85445f2 100644
--- a/lib/learn.c
+++ b/lib/learn.c
@@ -284,6 +284,14 @@ learn_to_nxast(const struct ofpact_learn *learn, struct ofpbuf *openflow)
     nal->len = htons(openflow->size - start_ofs);
 }
 
+static void
+learn_execute_nxm_load_cb(const struct ofpact_reg_load *src, struct ofpbuf *dst)
+{
+    struct ofpact_reg_load *load = ofpact_put_REG_LOAD(dst);
+    load->dst = src->dst;
+    load->subvalue = src->subvalue;
+}
+
 /* Composes 'fm' so that executing it will implement 'learn' given that the
  * packet being processed has 'flow' as its flow.
  *
@@ -323,7 +331,6 @@ learn_execute(const struct ofpact_learn *learn, const struct flow *flow,
 
     for (spec = learn->specs; spec < &learn->specs[learn->n_specs]; spec++) {
         union mf_subvalue value;
-        int chunk, ofs;
 
         if (spec->src_type == NX_LEARN_SRC_FIELD) {
             mf_read_subfield(&spec->src, flow, &value);
@@ -336,21 +343,15 @@ learn_execute(const struct ofpact_learn *learn, const struct flow *flow,
             mf_write_subfield(&spec->dst, &value, &fm->match);
             break;
 
-        case NX_LEARN_DST_LOAD:
-            for (ofs = 0; ofs < spec->n_bits; ofs += chunk) {
-                struct ofpact_reg_load *load;
-
-                chunk = MIN(spec->n_bits - ofs, 64);
-
-                load = ofpact_put_REG_LOAD(ofpacts);
-                load->dst.field = spec->dst.field;
-                load->dst.ofs = spec->dst.ofs + ofs;
-                load->dst.n_bits = chunk;
-                bitwise_copy(&value, sizeof value, ofs,
-                             &load->subvalue, sizeof load->subvalue, 0,
-                             chunk);
-            }
+        case NX_LEARN_DST_LOAD: {
+            struct ofpact_reg_load load = {
+                .dst = { .field = spec->dst.field, .ofs = spec->dst.ofs,
+                    .n_bits = spec->n_bits },
+                .subvalue = value,
+            };
+            nxm_load_split(&load, ofpacts, learn_execute_nxm_load_cb);
             break;
+        }
 
         case NX_LEARN_DST_OUTPUT:
             if (spec->n_bits <= 16
diff --git a/lib/nx-match.c b/lib/nx-match.c
index 17ef160..88e8a36 100644
--- a/lib/nx-match.c
+++ b/lib/nx-match.c
@@ -1019,14 +1019,39 @@ nxm_format_reg_move(const struct ofpact_reg_move *move, struct ds *s)
     mf_format_subfield(&move->dst, s);
 }
 
-void
-nxm_format_reg_load(const struct ofpact_reg_load *load, struct ds *s)
+static void
+set_field_format(const struct ofpact_reg_load *load, struct ds *s)
+{
+    const struct mf_field *mf = load->dst.field;
+    union mf_value value;
+
+    assert(load->ofpact.compat == OFPUTIL_OFPAT12_SET_FIELD);
+    ds_put_format(s, "set_field:");
+    memset(&value, 0, sizeof value);
+    bitwise_copy(&load->subvalue, sizeof load->subvalue, 0,
+                 &value, mf->n_bytes, 0, load->dst.n_bits);
+    mf_format(mf, &value, NULL, s);
+    ds_put_format(s, "->%s", mf->name);
+}
+
+static void
+load_format(const struct ofpact_reg_load *load, struct ds *s)
 {
     ds_put_cstr(s, "load:");
     mf_format_subvalue(&load->subvalue, s);
     ds_put_cstr(s, "->");
     mf_format_subfield(&load->dst, s);
 }
+
+void
+nxm_format_reg_load(const struct ofpact_reg_load *load, struct ds *s)
+{
+    if (load->ofpact.compat == OFPUTIL_OFPAT12_SET_FIELD) {
+        set_field_format(load, s);
+    } else {
+        load_format(load, s);
+    }
+}
 
 enum ofperr
 nxm_reg_move_from_openflow(const struct nx_action_reg_move *narm,
@@ -1066,6 +1091,43 @@ nxm_reg_load_from_openflow(const struct nx_action_reg_load *narl,
 
     return nxm_reg_load_check(load, NULL);
 }
+
+enum ofperr
+nxm_reg_load_from_openflow12_set_field(
+    const struct ofp12_action_set_field * oasf, struct ofpbuf *ofpacts)
+{
+    uint16_t oasf_len = ntohs(oasf->len);
+    uint32_t oxm_header = ntohl(oasf->dst);
+    uint8_t oxm_length = NXM_LENGTH(oxm_header);
+    struct ofpact_reg_load *load;
+    const struct mf_field *mf;
+
+    /* ofp12_action_set_field is padded to 64 bits by zero */
+    if (oasf_len != ROUND_UP(sizeof(*oasf) + oxm_length, 8)) {
+        return OFPERR_OFPBAC_BAD_ARGUMENT;
+    }
+    if (!is_all_zeros((const uint8_t *)(oasf) + sizeof *oasf + oxm_length,
+                      oasf_len - oxm_length - sizeof *oasf)) {
+        return OFPERR_OFPBAC_BAD_ARGUMENT;
+    }
+
+    if (NXM_HASMASK(oxm_header)) {
+        return OFPERR_OFPBAC_BAD_ARGUMENT;
+    }
+    mf = mf_from_nxm_header(oxm_header);
+    if (!mf) {
+        return OFPERR_OFPBAC_BAD_ARGUMENT;
+    }
+    load = ofpact_put_REG_LOAD(ofpacts);
+    load->ofpact.compat = OFPUTIL_OFPAT12_SET_FIELD;
+    load->dst.field = mf;
+    load->dst.ofs = 0;
+    load->dst.n_bits = mf->n_bits;
+    bitwise_copy(oasf + 1, mf->n_bytes, load->dst.ofs,
+                 &load->subvalue, sizeof load->subvalue, 0, mf->n_bits);
+
+    return nxm_reg_load_check(load, NULL);
+}
 
 enum ofperr
 nxm_reg_move_check(const struct ofpact_reg_move *move, const struct flow *flow)
@@ -1100,9 +1162,8 @@ nxm_reg_move_to_nxast(const struct ofpact_reg_move *move,
     narm->dst = htonl(move->dst.field->nxm_header);
 }
 
-void
-nxm_reg_load_to_nxast(const struct ofpact_reg_load *load,
-                      struct ofpbuf *openflow)
+static void
+reg_load_to_nast(const struct ofpact_reg_load *load, struct ofpbuf *openflow)
 {
     struct nx_action_reg_load *narl;
 
@@ -1111,6 +1172,80 @@ nxm_reg_load_to_nxast(const struct ofpact_reg_load *load,
     narl->dst = htonl(load->dst.field->nxm_header);
     narl->value = load->subvalue.be64[1];
 }
+
+void
+nxm_load_split(const struct ofpact_reg_load *in, struct ofpbuf *out,
+               void (*load_cb)(const struct ofpact_reg_load *load,
+                               struct ofpbuf *out))
+{
+    int chunk, ofs;
+
+    for (ofs = 0; ofs < in->dst.n_bits; ofs += chunk) {
+        struct ofpact_reg_load load;
+
+        chunk = MIN(in->dst.n_bits - ofs, 64);
+
+        load.dst.field = in->dst.field;
+        load.dst.ofs = in->dst.ofs + ofs;
+        load.dst.n_bits = chunk;
+        bitwise_copy(&in->subvalue, sizeof in->subvalue, ofs,
+                     &load.subvalue, sizeof load.subvalue, 0, chunk);
+        load_cb(&load, out);
+    }
+}
+
+static void
+set_field_to_ofast(const struct ofpact_reg_load *load,
+                      struct ofpbuf *openflow)
+{
+    const struct mf_field *mf = load->dst.field;
+    struct ofp12_action_set_field *oasf;
+    uint16_t padded_value_len;
+
+    oasf = ofputil_put_OFPAT12_SET_FIELD(openflow);
+    oasf->dst = htonl(mf->oxm_header);
+
+    /* Set field is the only action of variable length (so far),
+     * so handling the variable length portion is open-coded here */
+    padded_value_len = ROUND_UP(mf->n_bytes, 8);
+    ofpbuf_put_uninit(openflow, padded_value_len);
+    oasf->len = htons(ntohs(oasf->len) + padded_value_len);
+    memset(oasf + 1, 0, padded_value_len);
+
+    bitwise_copy(&load->subvalue, sizeof load->subvalue, load->dst.ofs,
+                 oasf + 1, mf->n_bytes, load->dst.ofs, load->dst.n_bits);
+    return;
+}
+
+void
+nxm_reg_load_to_nxast(const struct ofpact_reg_load *load,
+                      struct ofpbuf *openflow)
+{
+
+    if (load->ofpact.compat == OFPUTIL_OFPAT12_SET_FIELD) {
+        struct ofp_header *oh = (struct ofp_header *)openflow->l2;
+
+        switch(oh->version) {
+        case OFP12_VERSION:
+            set_field_to_ofast(load, openflow);
+            break;
+
+        case OFP11_VERSION:
+        case OFP10_VERSION:
+            if (load->dst.n_bits < 64) {
+                reg_load_to_nast(load, openflow);
+            } else {
+                nxm_load_split(load, openflow, reg_load_to_nast);
+            }
+            break;
+
+        default:
+            NOT_REACHED();
+        }
+    } else {
+        reg_load_to_nast(load, openflow);
+    }
+}
 
 /* nxm_execute_reg_move(), nxm_execute_reg_load(). */
 
diff --git a/lib/nx-match.h b/lib/nx-match.h
index f504ad0..f06af3e 100644
--- a/lib/nx-match.h
+++ b/lib/nx-match.h
@@ -65,12 +65,18 @@ enum ofperr nxm_reg_move_from_openflow(const struct nx_action_reg_move *,
                                        struct ofpbuf *ofpacts);
 enum ofperr nxm_reg_load_from_openflow(const struct nx_action_reg_load *,
                                        struct ofpbuf *ofpacts);
+enum ofperr nxm_reg_load_from_openflow12_set_field(
+    const struct ofp12_action_set_field * oasf, struct ofpbuf *ofpacts);
 
 enum ofperr nxm_reg_move_check(const struct ofpact_reg_move *,
                                const struct flow *);
 enum ofperr nxm_reg_load_check(const struct ofpact_reg_load *,
                                const struct flow *);
 
+void nxm_load_split(const struct ofpact_reg_load *in, struct ofpbuf *out,
+                    void (*load_cb)(const struct ofpact_reg_load *load,
+                                    struct ofpbuf *out));
+
 void nxm_reg_move_to_nxast(const struct ofpact_reg_move *,
                            struct ofpbuf *openflow);
 void nxm_reg_load_to_nxast(const struct ofpact_reg_load *,
-- 
1.7.10.4




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